Fluid-pressure-operated tool



- Nov. 24 1925.

E. H. SHAFF FLUI PRESSURE OPERATED TOOL 2 Sheets-Sheet l.l

Fned A'pn s, 1920 Nov. 24, 1925.

E. H. sHAFF FLUID PRESSURE oranusn Toor.

Filed April 5, 1920 2 Sheets-Sheet 2 sa ge connecting the Chamber 28 iv 'l ing shoulders against which the pressure of the motive fluid is exerted to move the valve member in opposite directions.

The handle head 14 provides an annular chamber 22 surrounding the rear end of the valve casing 20 and in constant eommunieation With the supply passage 16 for the live motive fluid.

The rear end of the valve easing 20 is provided With inlet means 28, whichma;7 coinprise an annular series of ports oommunioating With an internal annular groove in the valve easing, through which inlet means live motive fluid is introduced into the rear end of the piston chamber to move the piston on its forward or power stroke when the valve member 21 is in its forivird position as shown in Fig. 2.

The valve 2l is held in its forivard position by live air pressure in a rear valve chamber 24C acting upon the rear flange 25 on the valve member, the said Chamber being in constant communication with the sup` ply of live motive fluid through a small port 26.

The extreme forward end of tie storafije Chamber 19 is in constant Communication with the extreme forward end of the piston Chamber through suitable means such as grooves 27 out in the forward end of th inner tube 18. rIhe rear end of the storag chamber is in Constant communication with a valve chamber 2S through a su bie Airmber of ports or passages 29. The {err-.fard flange 2%0 on the valve member 2l moves in the valve chamber 28 and governed by the pressure in said ehainbe to shinA the v'alve rearwardly as will be later explained. wWhen the valve member is in its foi-Ward position the valve provides a retrieted pasan other Chamber 3l in the valve using and the latter chamber 3l is in consta-nt eoi'iiniu'nieation with the atmosphere through a suitable number of exhaiis;y passag s 2 leading therefrom to the exterior surface of the Cylinder l0. B v the ymeans described the spent Charge of motive fluid in the for iard portion of the piston chamber is permitted to exhaust through the storage ohar er and thence to the atmosphere ivhile the piston is traveling forward,

A passage 33 Conneets the rear portionv of the front valve chamber 28 with one of the exhaus"y passages another passage 34; Connects the rear portion of the rear valve chamber 2st with the piston chamber at a point forward of the valve 'lhe age Chamber 1Q and for f return of sueh nuid behind the piston prises in the preferred forni lier/einst" an annular series of ports 3o through the Wall of the inner tube 18, and means normally closing said ports and arranged to be operated by the pressure of the motive fluid in the piston chamber to open the ports and alioiv the escape of the motir'e fluid from the piston chamber into the storage Chamber.

l have shown in the drawings tivo alternative constructions of means for closing the ports 35. Referring rst to Figs. l, 3 and 4;, the said means form of an annular resilient valve member 36 which fits in an external annular groove 37 in the tube7 the ports 35 at their outer ends opening into said groove. in order to avoid undulf/i weakening the tube the latter is provided with an annular eftvernal onlin-freinent, the groove 37 being out in this en`a g lnient and providing tivo annular ribs 28 on the tube. Preferably also the ports 35 are drilled at an angle other than a right angle to the axis of the tube for the salie of strength.

The valve member is of be eled forniation and the bottom of the groove f' is tapered or inclined, so that when the motive fluid Within the piston chamber fi 'ees the valve member to expand it will also force a movement of the valve member l' 'h Wise of the tube along the tapered bfi-tom of the groove. The outer edge of the valve member is therefore moved into cont-art n 'tl the inner surface of the cylinder 10 as indioatedbv dotted lines in Fig. 2), When the pressure in the piston chamber is relieve the inheien; i' iene-y of the valve iiiei'nl/ior C2i-uses to eontraet and the tapered bot-tran wall of the groove forces the valve member to move axially of the tube into Contact with the upper edge of the groove so as to Close all the ports 35.

Referring non to the alternative ronstruetion shown in Figs. and (i. the 'valve means is in the forni of separate leaf springs fi() extending longitiiiflinaily of the tube ll and are suitably seein-ed to one end of the tube by suitable ineen.: sii-wh pins or rivets #il The o'iposiie oiid of earh spring overlies and nor uillv closes one of Y re of the tube 1H l so tha the signings tit the base or :iiitiiijhed end of each spring is eons'iderablv insider that the free end so that when the tiihe lb with. the attached snriiiii's thereon inserted into the oylinder the side er ges of the \i'id ne:l portions of the spring will be bent ii ,in to give a euri/'ed shape to spring. in this manner the spr' against vibration and are sti the free ends of the springs vd against the tube to eifeotivel ports 35.

n in notion the springs yield outwardly to the pressure Within the piston chamber and the portsA r being Hatteiiei tube snijioiv.

tl e surfe return to their politi-closing:r position when the pressures .in the storage and piston chambers are approximately balanced as set lorth in connection with the form of valve nie-ans lirst described.

The operation ot the tool lili l. to lf may be described as follows:

Let it be assumed that the main control 'alive 2l is in its forward position as shown lfigr. Qi, (beingv so held by the pressure in he rear valve chamber 2st), and that the iiston is at the rear end of the piston champ Live mot" fluid passes 'troni the supv chamber 2:3 through the inlets 23 into the rear cnil of the piston chamber, and acts to move the piston forwardly. The previs spent charge oit motive fluid/escapes 'trom the lorward end ol the piston chant her through the grooves 2i" into the storage chamber i9, thence through the passages 29 and ihroi. l1 the control valve and the chant ber ll and into the exhaust passages 32, and thence to the atmosphere.

When the rear end of the piston in travelline' li r\vardly uncovers the ports 35 in the inner tube the pressure olf the motive fluid will open the annular valve 30 and expand it outwaidly into contact with the iuterior ot the cylinder and the motive fluid will then pass into the storage chan'iber 19 and thence into the valve chamber 28.

inasmuch as the connection between the valve chamber 28 and the exhaust chamber il is a very restricted one, the pressure in the valve chamber will build up since the motive 'fluid cannot escape as tast it is admitted, and th-erejlfore the pressure acting as shown in Vupon the large 'Forward Vllange 30 oit the valve member will move the said valve meinber rearwardly in opposition to the pressure in the rear valve chamber 2l acting ou the much smaller flange .25 on the valve member. Vlhe pressure within the pistou chainbcr acting' upon the extreme `forward edn'e ol" the valve member also assists to shi'tt the valve rearwardly and approximately countcrbalances the etlect ot the pressure upon the rear flange and the pressure upon the thin extreme rear ond ot the valve member.

inasmuch as the expansible valve niemher B6 closes olie the liorward end ot the' storage '-liamber lt) the live motive- 'l-luid is at tiret prevented 'troni flowing into the loi-ward end ol the piston chamber and is instce d directed to the end ol.l the chamber to shift the. main control valve. The series ot ports may be located at any desired point along; the tube so as to be uncovered by the pieton in time to hll the storage chamber l) with motive tluid while the piston is linishing its working stroke. Thus the chamber l!) is tllled with motive fluid and the valve 2l is opened as the piston ll strikes the tool lil, thereby avoidimiV delay in the movement ot the pistou and recoil ot' the whole tool. Also the ports may be located suiliciently tar troni the liront end ot the piston chamber to permit ot using ditiferent length pistons.

lllhen the pressure inthe rear end ot the piston chamber and in the storage chamber has substantially equalized, the valve 256 will contract by its own resiliency and close the ports 35 whereupon the stored charge ot pressure fluid in the storage chainber l?) will tlow :forwardly through the passages 2? into the extreme forward end olf the piston chamber and move the piston on its return stroke.

By this time, the main control valve 2l. will have been shit-'ted into its rear position as seen in lfig. l, thereby exposing the eX- haust chamber 3l to the piston chamber and allowing,` the motive fluid in the rear portion ot the piston chamber to escape to the atmosphere, the inlet 3 tor live motive fluid havin,T been cut oliE by the rear end otl the main control valve 2l.

The motive tluid in the rear valve chant ber 2a'- will also be exhausted into the piston chamber through the passage Sel, and thence to the atmosphere. lllhen the piston in its rearward movement closes the iliorwurd end ot the passage Sil, the pressure in the rear valve chai'nber 2l builds up througgjh its supply port 2li and becomes su'llicient to shilit the main valve. 2l forwardly in opposition to the pressure on the larg-e flange 30 which has now been very much lowered by the utilization of the stored motive fluid in the storage chamber. lith the valve inember 2l in its Yforward position, a fresh charge ol live lnotivo 'fluid is introduced into the rear end of the piston chamber, and the cycle ot operation just described is repeated.

l claim as my invention:

l. A Afluid-pressure-operated tool having, in combination, a cylinder, an inner tube spaced from the interior of the cylinder to provide a storage chamber therebetween, the interior ot the tube iln'minii` a piston chamber, a piston freely movable in said pistou chamber, the cxtreme lor vard ends ot' the piston and storage chambers being in conimunication, au annular series ol ports through said tube at a point rcamvardolf the front end ot the pist-on chamber, a groove in the exterior ot said tube coinmunieating' with said ports, said groove having a, tapered bottoni wall` an expansible resilient annulai.' beveled valve member occupyingr said groove, the inclination ol" the beveled bottom wall of the groove cooperating with the valve member to hold the latter in position to close all oit said ports, said valve member beingarranged to be expanded by pressure within said piston chamber and to be moved along said tapered bottom wall ot the groove and into contact with the in lll) ierior of said cylinder whereby to cut oil' the forward portion of the storage chamber and direct the escaping motive fluid rearwardly, and suitable valve mechanism providing for inlet and exhaust of pressure fluid from sai-d piston chamber.

2. n a i'iuid-pressure-operated tool, a piston chamber, a separate storage chamber in communication with the forward end of said piston chamber, and means to provide communication between the storage chamber and the piston chamber at a point rearward from said forward end, said means including a valve member movable into a position in the storage chamber to separate said storage chamber into two parts and direct into the rear part the motive fluid escaping into the pistonchamber.

3. in a luid-pressure-operated tool, a piston chamber7 a separate storage chamber in communication with the extreme forward end of said piston chamber, a piston in said piston chamber, means to provide communication between said two chambers at a point spaced', rearward from their forward ends, and valve means including a valve member controlling the last-named means and movable outwardly under pressure from within the piston chamber to cut ofi' the forward portion of the storage chamber and direct the flow of motive fluid into the rear portion of the storage chamber, said piston being arranged to uncover and permit operation of said means on theforward or working stroke of said piston.

Li. A valvey for controlling the ilow of motive iiuid in a fluidpressure-actuated tool dapted normally to close a port leading from the piston chamber to a storage chamber but yieldable outwardly under the pressure of motive fluid in the piston chamber to permit the escape thereof to the storage chamber and forming a partition therein, said valve being in the form of a ring having an inclined wall positioned forwardly of said port when the valve is in its open position and operating to deflect motive fluid discharging` from said port to the rear portion of the storage chamber.

A valve means for controlling the How of motive fiuid in a fluid-pressure-actuated tool including a valve member normally operating` to close a plurality of annularly arranged ports leading from the piston chamber to a storage chamber but yieldable outwardly under the pressure of motive iiuid in the piston chamber to permit the escape thereof to the storage chamber, said valve forming when in open position a partition in the storage chamber confining the pressure fluid to the rear portion of the chamber.

In testimony whereof, I have hereunto set my hand.

ERNEST H. SHAFF. 

